Bending machine



M. s. DICKINSON ET AL ,2 ,992

BENDING MACHINE June 24, 1941.

Filed March 4, 1959 2 Sheets-Sheet 1 IIIlIIIII/l; -e 7 J1me 9 M. s. DICKINSON ETAL ,246,992

BENDING MACHINE Filed March 4, 1939 2 Sheets-Sheet 2 INVENTORS 772% J 0W, mud

Patented June 24, 1941 BENDIN G MACHINE Merville S. Dickinson,

Edgeworth, and Edward L.

Born, Coraopolis, Pa., 'assignors to Draw Corporation, a corporation of Pennsylvania Application March 4, 1939, Serial No. 259,860

3 Claims.

This invention relates to metal bending apparatus. Though applicable in the bending of elongate bodies of metal generally, it has been developed in the bending of steel bars; and,

specifically, of I-beams; and in such association it will be illustrated and described. The ob jects in view are precision, economy, and speed of production.

In the accompanying drawings Fig. I is a View in. horizontal section of a bending machine in which and in the operation of which the inven-, tion is realized. Fig. 11 is a View of the same machine in vertical section. The plane of section of Fig. I is in Fig. II indicated by the broken line.II, and the plane of section of Fig. II is indicated in Fig. I at lI-II. Fig. III is a fragmentary view in vertical section on the plane indicated at III-III, Fig. I. Figs. IV and V are views corresponding to Fig. I of a machine of more elaborate structure and illustrative of further features of invention, both in structure and in method. Fig. VI is a fragmentary view in elevation in the field of View indicated in FigLIV by the line VI.VI and the associated arrows.

The bending machine of the in ention consists essentially of a pair of relatively reciprocable dies, between whichmefial bars are bent. As shown, the dies are reciprocable on horizontal lines, but that feature will be understood to be merely a matter of convenience.

Referring particularly to Figs. 1, II, and III,

the two dies are indicated at l and 2 and the work upon which they operate is shown in the form of an I-beam B. Fig. I is diagrammatic, particularly in that it shows but half of the machine; the line a a is the centre-line, and it will be understood that the structure to the right of this line is in fact duplicated symmetrically to the left.

The male die I has a convex face 3 to which in machine operation the work B is shaped. The female die is compound. It consists of a support, to which. the numeral 2 is immediately ap-' plied, and which is shown to be a rugged box or other, define a. work-occupied space:

th Wor s shaped substantially greater in radius than, and preferably approximately equal in radius to the curvature of the face 3 of the male die. The surfaces of the ends 6 of the blocks conform to cylinders of vertically arranged axes, and are of. a breadth (vertically) 'suited tothe work. Both dies are, by the features of shape that have been 1 scribed, adapted initially to engage the surfaces of the work tangentially, ;.on vertical lines ol tangency. When ,the'dies are, .closed, the faces 5 of the, blocks 4 make surface to surface contact withthe Work.

Means for eifecting relative reciprocation of the dies in the direction of the centre-line a-a, not shown, will be understoodto be proyided.

Referring particularly to Fig. I and to the fullline showing of that figure, it will be remarked that the blocks a e swung to positions in which their ends lie in a common vertical plane, perpendicular to. the centre-line of the machine; and, the blocks being in such position, a small range in the .relatiyereciprocation of the dies sufiices, to permit, the endwise introduction of the work B, to the. position illustrated. A plate a 8 borne, the mal eaffo ds suppo t o h work, and brackets 80., 8| borne by theflblocks 4 cooperate to hold the work against displacement asthedies closeuponit. I

The dies close upon the work B when brought to the position shown, in full lines in Fig. I. It will be remarked that, at the beginning of the bending operation, the male die is tangentto the work on one side and at a middle point, and that the two blocks 4 are at their ends B tangent to the work on the oppOsite side, each at two pointsspaced at successive intervals onthe two sides of the point of .tangency of the male die.

The dies close. In this case .the male die ad vances from the full-line position shown to the dotted-line position.v As it advances the blocks 4 swing pivotally to the dotted-line position, and upon the convex face 3 of die I to; the dottedeline position. In this advance it will be remarked (I) that, by virtue of the pivotal mounting of the blocks, the bending v n the work' at the Dointsof enga ementof theblocks isequalized between the points of bearing; (2 that the convex face 3 of the male die on the one side, and the convex'faces of the ends 6 of the blocks 4 on the a space that, initially rectilinear in extent, becomes curved as the dies close, and thatthe curvature, as die-closing progresses, decreases in radius,'un-

pressure'brought to bear upo til it corresponds to the curvature of the face 3 of the male die; (3) that throughout the closing stroke the ends 6 of the blocks 4 engage the work at spaced apart points (leaving the intervening length of work to respond freely to the bending stress), until at length the dies are fully closed, when for the first time the concave surfaces 5 of the blocks come to surface bearin upon the now fully bent piece of work, and exert upon the bentpiece a distributed compressive stress; (4) that the bending is effected under very much smaller stress than would be requisite were the work-engaging face of the female die a fixed and continuous surface; and (5) that the stood that the blocks 4 maybe pivotally'rnounted in any of the correlated pairs of orifices ll. It will be apparent that, as the spacing of the blocks is variedtransversely of the line offdirection of die reciprocation, the work itselfbeing of uniform transverse section, thelextent of the'curvature may be varied longitudinally of the piece of work; and that, as the position of the blocks 4 is varied longitudinally of the direction of die reciprocation, the efiective depth of the stroke of the reciprocating dies may be varied, even though no change bemade in the actual length of stroke of the moving die (in this case the male die I) rela tively to the fixed die 2 We have found that for an I-beam whosecentral web is'of a given breadth (ah-b, Fig. I) there isan ideal position for the pivoting of the blocks 4--a position such that in the bending operation the relative movement of the ends 6 of the blocks upon the surface of the work (in any case slight) may be practically eliminated. The effective stroke of'the die I may be minutely varied by means of shims l2, adjusting the position of. thedie 2 in the bed 9.

It will be remarked that, when the die is completely closed, the outer end of the block. 4, is in substantial alignmentswithithe outer end of the convex face of die i. This is'an advantageous though. not. an essential feature in the proportioning of parts, I

Fig. III serves to show work B restrained above and below by the brackets. 80 and BI ;as the dies close upon it. A rolled steel I-beam, herechosen for purposes of illustration, is an article that is flexible and susceptible tobending, butit possesses a certain elasticity too, and,.when released b t v w y he Opemng of the dles Sprmgs shghtly from 60 so much as is' ultimately to be shaped. The dies the curvature to which it is brought whenlthe dies are fully closed, and assumes a curvature of slightly longerradius. When curvature for the finished article is specified, it will beunde'rstoodthat a maledie i will be. employed,whose work-engaging face 3.is curvedto a su'fliciently smaller radius; and it need only beaddedthat, when dealing with I-beams of givencross-section, the proper curvature for the face of .themale. die may be empirically determined-,-. to afford afinished articleof curvature of desired radiuswell within the margin of tolerance permissible in suchwork, f I

Turningto Figs. IV-VI of. the drawings, certain elabor'ations of structure and of vmethodlare 7 to be explained. The ends of the blocks 4i! are shown to be equipped with rollers 50, whose effeet in the bending operation is to reduce frictional wear, through the range of relative movement (ordinarily slight) at the lines of contact. To the outer end of each block 40 a second block 1 is freely pivoted on a vertical axis. This second block may be swung at will between the inactive position shown in Fig. IV and the active position shown in Fig. V. The block 1 is essentially such 10 in shape as the block 49: when in operative position it presents to the work a concave face, not greater. in radius of curvature than the opposed face of the male die I; it is equipped at its two endswith rollers 10 that in operation engage the work-at spaced-apart points at successively greater distances from the centre-line of the machine; and, while theinner end of block 1 is nearer the centre-line of the machine than the outer end of block 40, the two ends of block 1 together have their shaping effect in a portion of the work more remotejfrom the centre-line of the machine thanthe portion upon which block'40 has effect; and, 'accordingly, we characterize the engagement of the block '1 with the work as an engagement at? two points more remote from the point of initial tangency of the male die with the ;work than the two-point engagement of. the block 40 with the work. 7 j

, Figs. IVjand V show the faces of blocks 40 to be more deeply concave than those of blocksfl4 of Fig, I; and while in this. case,as is particularly manifest from thedotted-line showing of Fig. IV, the block does not; even. onthe completion of the closing movement of the dies, abutupon the work,

over all the extent'of the concave face,'the deeper concavity, here is advantageous inaffording' space for the free play of the second block 1 in performing its partinthe operation (cf. Fig. V),

The operationof the machinein the .more elaborate structure ofFigs. IV -VI is advantageously a two-step operation; and the method performed is a two-step and; progressive method, withthe adVantages'first, that in the progress of, the bending roperation the work is more certainly stabilized in position, and thedangerof tipping is more certainly guarded against; second, that greater. uniformity in curvature throughout theglength of the article is gainedflthird; that less power is required and wear and tear are less.

operation, then, initially, the blocks 1 of the second pair are swung aside, to the position indicated in Fig. IV. With the parts so arranged, the first step in the operation is identically that already described with'reference to Figs. I and II. In this initial stepthework isbent substantially to ultimate form from the'centre-line of the machine outward throughout part only of'the extent of the piece or throughout partonly of inactive position of Fig. IV to the active position of Fig; Y whereupon ('thework: remaining properly centered) the dies are closed again and then, as particularly showriin Fig. Vj, the work in-regions moreremote fro'rnthe centre-line of machine isbythe cooperationof theblocks 1 with the male die shaped'to the'fac'e of the' male die! T ew dIb rdi u e m gi the first; and completes the bendin g of the piece of' work. In this two-step operation th I twofreciprocations of jdi e I will be throughjidentically the same a range; but on the .sefiond reciprocation the bend ing effect of the blocks 1 will be supplementary to that of the blocks 40 in the first reciprocation.

As has been said and as shown in Fig. I, the outer end of the block 4 (the right-hand end) is when the dies are closed in substantial alignment (in the direction of die-movement) with the outer end of the face 3 of the male die against which the work is shaped. In Fig. V it appears that in the ultimate closing of the dies the outer end of the second block 1 extends to the right, beyond the limit of the face of the male die. It will be realized that, particularly with work of substantial breadth (in the direction of die reciprocation) some excess here of the extent of the engagement of the female die upon the convex face of the shaped piece of work may be found desirable.

The circumferential extent of the curve to which the beam is shaped is, in the exemplary showing of the drawings, about 90. It is manifest that precisely as, in the machine of Figs. IVVI, the bending by means of the blocks 1 supplements that by means of blocks 40, so by shifting of the work in its position between the dies the bending effected in one operation may be supplemented by bending in a succeeding operation, and so the circumferential extent of the bending may (within the limits imposed by the length of the article) be extended indefinitely.

We have chosen for purposes of an I-beam as the specific material that in the operation of the machine is bent. It is manifest that the invention is applicable to the bending of elongate metal articles generally.

We claim as our invention:

1. In apparatus for bending a length of metal that includes a die having a convex face, a support and a die-block with concave face pivotally mounted upon said support, the two said die members being relatively reciprocable, and adapted simultaneously to engage a length of metal when brought to position between them and by reciprocation to effect a bending thereof in an intermediate portion of its extent, the invention herein described which consists in the provision for a range of further reciprocation between the convex-faced die and the said support, and a second die-block with concave face pivotally mounted intermediate its ends upon the first-named concave-faced die-block and adapted to be swung to and from a position of cooperation with the convex-faced die, and adapted in such position of cooperation to engage by its two ends simultaneously the length of metal illustration under treatment and in the further reciprocation between the convex-faced die and the support to effect a bending of the length of metal in a terminal portion of its'extent.

2. In metal-bending apparatus including a male die having an extended band-like face shaped in one plane to a convex curved surface and a female die, the two said dies being mounted for relative reciprocation, the invention herein described in which the female die includes a support, a beam pivotally mounted upon said support on an axis perpendicular to the plane in which the face of the male die is curved, and having on either side of its pivotal mounting abutments adapted simultaneously to engage at spaced-apart points a piece of work introduced between the :dies, together with a second beam pivoted upon the first at a point to one side of the pivot of the first-named beam upon the support, the second-named beam having at either side of its pivotal mounting abutments adapted simultaneously to engage at spaced-apart points such piece of work introduced between the dies, the second-named beam being movable upon its pivot from a remote position to a position of cooperation with the male die.

3. In metal-bending apparatus including a male die having an extended band-like face shaped in one plane to a convex curved surface and a female die, the two said dies being mounted for relative reciprocation, the invention herein described in which the female die includes a support, a pair of beams pivotally mounted upon said support on axes perpendicular to the plane in which the face of the male die is curved, each having on either side of its pivotal mounting abutments adapted simultaneously to engage at spaced-apart points a piece of work introduced between the dies, together with a second pair of beams pivoted severally upon the beams of the first pair at points to one side of the pivots of the first-named beams upon their support and at points that in the assembly are outward from the pivots of the first-named beams upon their support, the beams of the second pair in turn having each at either side of its pivotal mounting abutments adapted simultaneously to engage at spaced-apart points such piece of work introduced between the dies, the beams of the secondnamed pair being movable upon their pivots from remote positions to positions of co-operation with the male die.

MERV'IILE S. DICKINSON. EDWARD L; BORN. 

